Semiconductor devices evolved to be more minimized, to have larger storage capacity, and to be multifunctional. Recently, a multi chip package (MCP) having a structure formed by stacking the same or different semiconductor chips has been newly introduced.
In order to stack semiconductor chips on a semiconductor package, an MCP requires each semiconductor chip to be grinded to be thin, and requires a wire height to be low in a wire bonding process in which each semiconductor chip is electrically connected to a printed circuit board (PCB) included in the semiconductor package. Also, a die attach film used to attach each semiconductor chip has to be as thin as possible. However, in spite of all these efforts, since there is limit in stacking a plurality of semiconductor chips on one semiconductor package, research has been continuously conducted.
Meanwhile, in order to solve such a limit, a through silicon via (TSV) connecting method is developed to form a TSV in a bond pad of a semiconductor chip, to fill the TSV with a conductive material, and to vertically interconnect the semiconductor chips with another semiconductor chip, and is to be commercialized soon.
The aforementioned TSV connecting method for forming vias in a bond pad of a wafer by using a laser is disclosed in U.S. Pat. No. 7,118,989 (published on Oct. 16, 2006, introduced by Ramanathan, Shriram/Intel Corporation), entitled “Method of forming vias on a wafer stack using laser ablation”.